1. Field of the Invention
The invention relates to a height-adjustable docking buffer, particularly for protection during loading and unloading operations for vehicles at building openings, consisting of a mounting frame and a height-adjustable buffer block for a loading ramp or a transfer bridge.
In addition, the invention relates to a process for operating a docking buffer.
Trucks are loaded at warehouses almost exclusively on loading ramps, which should be at approximately the height of the vehicle loading surface. Also known are transfer bridges that enable an adjustment between the level of the loading ramp and the level of the vehicle loading surface, which changes depending upon the loading status.
2. Discussion of the Prior Art
The German Utility Model DE 92 01 381 U1 describes a docking buffer for ramps that adjusts to the upward and downward movements of the vehicle during loading and unloading, and thus prevents damage to the buffer and its means of attachment. In its resting position, i.e. the normal position, this buffer is located at ramp height, and can then be raised or lowered by a truck. In this known configuration, it is not possible to adjust the buffer to a height above or below the ramp. Nevertheless, the situation has repeatedly arisen wherein the ramp height is significantly lower than the height of the vehicle loading surface, with the result that the vehicle overshoots the edge of the ramp and thus in some circumstances damages the building door, building facade, or vehicle. To prevent this, the generic German patent DE 195 48 121 proposes that the buffer block be adjustable in its initial position over the surface of the loading ramp or transfer bridge. Such a docking buffer, which protrudes over the top edge of the ramp, interferes when opening the truck's door. Because the buffer block interferes during the loading process, it must be lowered so that its upper edge is flush with the ramp height, and can no longer obstruct the loading process. The solution to the problem of lowering the buffer when a truck is exerting pressure on the buffer is solved only insufficiently and thus disadvantageously with the state of the art. In the state of the art, when under pressure from the docked vehicle, the buffer can be lowered only by removing a wedge or displacing a cam so as to introduce play into the mechanism and thus enable the buffer to be lowered.
It may also occur, however, that the loading surface of the docking truck is lower than the height of the ramp edge. In such cases, the vehicle and building should also be protected against damage when docking.
A special problem presents itself when, for specific reasons, e.g. temperature controlled logistics chains such as those for refrigerated buildings, no building wall is available to mount a docking buffer. Examples of such devices to seal the gap between the edge of a building opening and the rear of a docked vehicle can be found in DE 33 42 732 A 1, DE 37 10 528 A 1, DE 30 49 358 C 2, DT 25 55 201 A 1, and DE 199 06 486 C 1. All of these devices have in common the fact that they seal the gap only at the sides and the top between the building opening and a vehicle docking at this building opening. At the bottom, the gap between the building opening and the vehicle is only partially sealed by a transfer bridge, whose platform is placed upon the vehicle's loading surface in order to load or unload the vehicle.
The disadvantages of these known concepts is that openings remain between the lateral seals and the transfer bridge, through which air exchange can occur between the outside air and the inside of the loading station. Because of the necessary positional tolerances of a vehicle docking at the building opening, the transfer bridges must always be narrower than the vehicle's loading surface. The aforementioned openings are thus necessitated by the system. These openings constitute a disadvantage, e.g. particularly in the case of logistics chains for deep frozen goods that require maintenance of a specific temperature or a specific climate for the items being transported. Moreover, in the case of refrigerated buildings, the transfer bridges may freeze over because the warm air entering the area condenses existing moisture on the upper surface of the transfer bridge. The resulting dew may also freeze, which presents a hazard to workplace safety. For such situations, GM 7425832.5 or DE 2306130, for example, describe gaskets that seal the gap between the building opening and a docked vehicle above and at the sides. In addition, U.S. Pat. No. 4,293,969 describes an inflatable gasket that forms the seal between a floor of a transfer bridge and the base of the depression.
A disadvantage of the known solutions is that an unsealed opening always remains on either side of the rear end of the vehicle and the transfer bridge.
Nevertheless, there is an urgent need to automate the entire loading process, even for different structural situations, and to improve safety both inside and outside.